Toddler dies after months of delay in diagnosing SMA type 1

Case highlights difficulties of detecting, treating SMA in developing countries

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by Andrea Lobo |

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A young girl whose muscle weakness and respiratory distress in infancy were treated only as such was diagnosed as a 1-year-old with a severe form of spinal muscular atrophy (SMA), scientists in Pakistan report.

She died shortly after her SMA type 1 diagnosis, and after starting on supportive measures and physiotherapy that might have helped months earlier.

“The lack of effective treatment and the challenges in diagnosis and management make it crucial to raise awareness and establish appropriate protocols for identifying and treating SMA cases, particularly in countries like Pakistan where resources are limited,” the scientists wrote.

Her case also “emphasizes the value of early detection, interdisciplinary care, genetic testing, and novel therapeutics in terms of improving outcomes,” they added.

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Breathing and movement difficulties in infancy failed to lead to SMA diagnosis

Her case was reported in “Spinal muscular atrophy type 1: A fatal case in a 1-year-old girl with delayed diagnosis,” published in the journal Clinical Case Reports.

SMA mostly is caused by inherited mutations in the SMN1 gene, which encodes for the survival motor neuron protein (SMN). A result is the progressive loss of motor neurons, the specialized nerve cells that control voluntary movement, and the onset of disease symptoms, including muscle weakness and wasting (atrophy).

The disease is clinically classified into five main types, according to the age at which symptoms first appear, and estimated to affect about 1 in every 8,000 to 10,000 live births worldwide.

However, “its prevalence level is unknown in Pakistan due to a lack of awareness and diagnostic facilities,” the scientists wrote.

They presented the case of a 1-year-old whose initial symptoms were never linked with SMA, and no genetic testing was done in infancy.

The girl had a normal birth, but her mother reported observing reduced muscle strength in the child’s legs, feet, and extremities at age 3 months. By the age of 8 months, her respiratory problems led to several hospital admissions, with complaints of respiratory distress and pneumonia, a type of lung infection.

As a 1-year-old, she arrived at a Karachi hospital’s emergency department with complaints of cough and respiratory distress for two weeks. She was given intravenous (into-the-vein) antibiotics, and a chest X-ray showed a lung infection.

Further examination found generalized low muscle tone (hypotonia), limb muscle weakness, absent reflexes, and constant tongue movement. Due to a history of muscle weakness and respiratory distress in a paternal uncle, doctors began to suspect SMA.

Diagnosing and treating SMA in developing countries remains a ‘challenge’

Multiple disease-related tests began, including electromyography (EMG) to assess the health of muscles and the motor neurons that control them, and nerve conduction tests to measure the speed of electric signals traveling through a specific nerve. Genetic testing also revealed a mutation in both SMN1 gene copies, and two copies of the SMN2 gene, a “backup” gene that accounts for the production of about 10% of functional SMN protein.

She then was diagnosed with SMA type 1.

Although the child needed ventilator support due to severe respiratory distress, the parents did not give their consent. Instead, the girl was kept on continuous supplemental oxygen and given antibiotics to treat her pneumonia. She also was given physiotherapy support, postural changes, and frequent nebulization and suction to drain her mucus.

The girl died 20 days after starting on such treatment and support.

According to the scientists, this case highlights the need for an early SMA diagnosis and a start on available disease-modifying treatments. They also noted that countries with newborn screening programs for SMA allow for the disease to be detected before symptom onset, when treatment is most effective.

However, “in Pakistan, diagnosis of and treatment for SMA children remains a challenge due to the lack of newborn screening programs for SMA and the high cost of US FDA-approved SMA drugs,” the scientists wrote.

“Our case sheds light on the various management strategies, including supportive care, respiratory support, and physical therapy. This information can be valuable for clinicians who may encounter similar cases,” they added. “Therefore … it is desirable to first diagnose and report such cases in Pakistan and treat them accordingly to increase the survival ratio among SMA Type 1 patients.”